Multiphoton entanglement and interferometry

TLDR

Multiphoton interference exposes strictly nonclassical phenomena and underpins fundamental tests of quantum mechanics and photonic quantum information processing. This review surveys recent theoretical and experimental progress in multiphoton entanglement and interferometry. It focuses on creating photonic entanglement, testing local realism, and applying these results to quantum communication protocols and linear‑optics quantum computation, limited to few‑photon discrete‑observable experiments.

Abstract

Multiphoton interference reveals strictly nonclassical phenomena. Its applications range from fundamental tests of quantum mechanics to photonic quantum information processing, where a significant fraction of key experiments achieved so far comes from multiphoton state manipulation. The progress, both theoretical and experimental, of this rapidly advancing research is reviewed. The emphasis is given to the creation of photonic entanglement of various forms, tests of the completeness of quantum mechanics (in particular, violations of local realism), quantum information protocols for quantum communication (e.g., quantum teleportation, entanglement purification, and quantum repeater), and quantum computation with linear optics. The scope of the review is limited to ``few-photon'' phenomena involving measurements of discrete observables.